JP2007192907A - Positive photosensitive composition and pattern forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photosensitive composition for use in the production process of a semiconductor such as IC, in the production of a circuit substrate of liquid crystal, thermal head and the like or in other photofabrication processes, the positive photosensitive composition being stable to environmental variation and having high sensitivity and high resolution, and to provide a pattern forming method using the same. <P>SOLUTION: The positive photosensitive composition contains (A) a compound having a group (a) of which the hydrophilicity is increased upon irradiation with an actinic ray or radiation and (B) a compound having a group (b) which is decomposed by the action of an alkali to increase solubility in an alkali developer and not having a group which is decomposed by the action of an acid, or contains (AB) a compound having the group (a) of which the hydrophilicity is increased upon irradiation with an actinic ray or radiation and the group (b) which is decomposed by the action of an alkali to increase solubility in an alkali developer and not having a group which is decomposed by the action of an acid. The pattern forming method using the same is also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a positive photosensitive composition whose properties change upon reaction with irradiation of actinic rays or radiation, and a pattern forming method using the same. More specifically, a positive photosensitive composition used in semiconductor manufacturing processes such as IC, circuit boards such as liquid crystal and thermal head, other photofabrication processes, lithographic printing plates, and pattern formation using the same Regarding the method. More specifically, a positive photosensitive composition suitable for use as an exposure light source such as ultraviolet light or deep ultraviolet light of 400 nm or less, preferably 250 nm or less, more preferably 200 nm or less, and an irradiation source using an electron beam or the like, and the same are used. The present invention relates to a pattern forming method.

As the positive photosensitive composition, a composition containing an alkali-soluble resin and a naphthoquinonediazide compound as a photosensitive material is generally used. For example, examples of “novolak type phenolic resin / naphthoquinone diazide substituted compound” are disclosed in US Pat. No. 3,666,473 (Patent Document 1) and US Pat. No. 4,115,128 (Patent Document 2). And US Pat. No. 4,173,470 (Patent Document 3) and the like, and the most typical composition is “a novolak resin comprising cresol-formaldehyde / trihydroxybenzophenone-1,2-naphthoquinonediazide”. Examples of “sulfonic acid esters” are described in Thompson “Introduction to Microlithography” (ACS Publishing, No. 2, 19, p112 to 121) (Non-patent Document 1). Yes. In such a positive photosensitive composition comprising a novolak resin and a quinonediazide compound, the novolak resin has an alkali-soluble function, and the naphthoquinonediazide compound acts as a dissolution inhibitor. And naphthoquinone diazide has the property of losing its ability to inhibit dissolution by generating carboxylic acid when irradiated with light and increasing the alkali solubility of the novolak resin.
On the other hand, chemically amplified photosensitive compositions are described in US Pat. No. 4,491,628 (Patent Document 4), European Patent 249,139 (Patent Document 5), and the like. The chemically amplified photosensitive composition is composed mainly of a compound that generates an acid upon irradiation with actinic rays or radiation such as far ultraviolet light and an acid-decomposable compound, and is exposed to an actinic ray or radiation such as far ultraviolet light. The acid-decomposable compound decomposes and releases alkali-soluble groups by the reaction using this acid as a catalyst, thereby changing the solubility of the active light or radiation irradiated and non-irradiated areas in the developer. And a pattern forming material for forming a pattern on the substrate. The chemical amplification photosensitive composition, in principle, has a quantum yield exceeding 1, and thus exhibits high photosensitivity and can be a better system than the conventional naphthoquinone diazide / novolak resin system, while a small amount of acid catalyst. In the image forming process, image formation defects due to contamination of the base component and performance changes due to changes in the post-heating temperature are large. In order to form a pattern stably, it is necessary to strictly carry out process management and quality control in each process, such that the image formability is greatly changed.

US Pat. No. 3,666,473 US Pat. No. 4,115,128 U.S. Pat. No. 4,173,470 US Pat. No. 4,491,628 European Patent No. 249,139 Thompson "Introduction to Microlithography" (ACS Publishing, No. 2, 19, p112-121)

  An object of the present invention is to provide a positive photosensitive composition that is stable against environmental changes, has high sensitivity, and high resolution, and a pattern forming method using the same.

  The present invention is as follows.

(1) (A) A structure having a structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation and (B) a structure which is decomposed by the action of an alkali and increases the solubility in an alkali developer (b) And a positive photosensitive composition comprising a compound having no group capable of decomposing by the action of an acid.

(2) (AB) having a structure (a) in which hydrophilicity is increased by irradiation with actinic rays or radiation, and a structure (b) in which decomposition is caused by the action of an alkali and solubility in an alkali developer is increased, and A positive photosensitive composition comprising a compound having no group capable of decomposing by the action of an acid.

  (3) The structure (b) according to (1) or (2), wherein the structure (b) which decomposes by the action of an alkali and increases the solubility in an alkali developer is a lactone group or an acid anhydride group Positive photosensitive composition.

  (4) Any of (1) to (3), wherein the structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation is a structure which generates an acid upon irradiation with actinic rays or radiation. The positive photosensitive composition described in 1.

  (5) At least one compound selected from the compound (A), the compound (B) and the compound (AB) further has an alkali-soluble group (1) to (1) 4) The positive photosensitive composition in any one of.

  (6) The positive photosensitive composition as described in any one of (1) to (5), further comprising (Ca) a resin having an alkali-soluble group.

  (7) A pattern formation comprising a step of forming a photosensitive film from the positive photosensitive composition according to any one of (1) to (6), and exposing and developing the photosensitive film. Method.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a positive photosensitive composition that is stable against environmental changes, has high sensitivity, and high resolution, and a pattern forming method using the same.

  In the description of the group (atomic group) in this specification, the notation which does not describe substitution and non-substitution includes the thing which has a substituent with the thing which does not have a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

The positive photosensitive composition of the present invention is decomposed by the action of (A) a compound having a structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation, and (B) an alkali. A compound having a structure (b) having increased solubility and not having a group capable of decomposing by the action of an acid, or (AB) a structure having increased hydrophilicity by irradiation with actinic rays or radiation ( a) and a compound that has a structure (b) that decomposes by the action of an alkali and increases the solubility in an alkali developer and does not have a group that decomposes by the action of an acid.

  The positive photosensitive composition of the present invention has a completely different image forming mechanism from the conventional novolac type phenol resin / naphthoquinone diazide compound composition and chemical amplification type photosensitive composition. When the photosensitive film formed using the positive photosensitive composition of the present invention is subjected to pattern exposure, the structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation at the exposed portion is decomposed and exposed. The hydrophilicity of the part increases. The alkali developer penetrates into the film due to the increased hydrophilicity in the exposed area during the development process. The permeated developer is decomposed by the action of the alkali, decomposes the structure (b) whose solubility in the alkali developer is increased, the alkali solubility is further increased, and only the exposed portion is selectively dissolved. Therefore, unlike the chemically amplified photosensitive composition, the positive photosensitive composition of the present invention does not require a structure that decomposes by the action of an acid. Further, by using a chemical reaction in an alkali development process, an image can be formed with higher sensitivity than a novolac type phenol resin / naphthoquinonediazide compound composition.

A compound having a structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation (also referred to as “compound (A)”)
The structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation is decomposed by irradiation with actinic rays or radiation, and at least one of the generated functional groups is more hydrophilic than the structure before irradiation. Represents that. For example, the hydrophilicity can be evaluated by comparing the LogP value or I / O value of the compound before irradiation with the compound after irradiation, and the decrease in the LogP value or the increase in the I / O value can be achieved. If seen, it means that the hydrophilicity has increased.

  In the compound (A), the structure (a) whose hydrophilicity increases upon irradiation with actinic rays or radiation is preferably a structure capable of generating an acid upon irradiation with actinic rays or radiation. The compound (A) may be a resin having a structure that generates an acid upon irradiation with active light or radiation, or may be a low-molecular compound having a structure that generates an acid upon irradiation with active light or radiation. .

  Examples of the compound having a structure that generates an acid upon irradiation with actinic rays or radiation include a photoinitiator for photocationic polymerization, a photoinitiator for photoradical polymerization, a photodecolorant for dyes, a photochromic agent, or a micro resist. The compound which generate | occur | produces an acid by irradiation of the actinic ray or radiation currently used for can be mentioned.

  Examples include compounds having structures such as diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime esters, oxime sulfonates, diazodisulfones, disulfones, o-nitrobenzyl esters, o-nitrobenzyl sulfonates, naphthoquinone diazides. be able to.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,137, German Patent No. 3914407. JP, 63-26653, JP, 55-164824, JP, 62-69263, JP, 63-146038, JP, 63-163452, JP, 62-153853, Examples thereof include compounds described in Japanese Utility Model Publication No. 63-146029.

Furthermore, the compound which generate | occur | produces an acid by the light as described in US Patent 3,779,778, European Patent 126,712, etc. can also be mentioned.

  Among the compounds having a structure capable of generating an acid upon irradiation with actinic rays or radiation, compounds having a structure capable of generating a carboxylic acid upon irradiation with actinic rays or radiation can be exemplified.

As a structure which generate | occur | produces an acid by irradiation of actinic light or a radiation, the structure represented by the following general formula (ZI)-(ZVII) can be mentioned, for example.
The compound (A) preferably has at least one structure selected from these.

In general formulas (ZI) to (ZVII),
Ya is, -C (= O) - or -SO ₂ - represents a.
Ra represents a monovalent organic group.
Xa ₂ represents a monovalent organic group.
Xa ₃ and Xa ₄ each independently represent a hydrogen atom or a monovalent organic group.
Xa ₁ represents a divalent organic group.
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents a monovalent organic group. Two members out of R _{201 to} R ₂₀₃ may combine to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group.
_R204 and _R205 each independently represents a monovalent organic group.
R ₂₀₆ and R ₂₀₇ each independently represents a monovalent organic group.
X- represents an anion.

In the general formulas (ZI) to (ZVII), examples of the monovalent organic group represented by Ra include an alkyl group, a cycloalkyl group, an aryl group, and an aralkyl group.
The alkyl group of Ra is preferably a linear or branched alkyl group having 1 to 15 carbon atoms, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl. Group, pentyl group, isopentyl group, neopentyl group, t-pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group Group, octadecyl group, nonadecyl group, eicosyl group and the like.
The cycloalkyl group of Ra may be monocyclic or polycyclic. The monocyclic type is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. As the polycyclic type, a cycloalkyl group having 6 to 20 carbon atoms is preferable. For example, an adamantyl group, norbornyl group, isobornyl group, camphanyl group, dicyclopentyl group, α-pinel group, tricyclodecanyl group, tetracyclododecyl group. Group, androstanyl group and the like.
The aryl group of Ra is preferably an aryl group having 6 to 16 carbon atoms, and examples thereof include an aryl group composed of a hydrocarbon and a heteroaryl group having a heteroatom such as a nitrogen atom, a sulfur atom, or an oxygen atom. The aryl group composed of hydrocarbon is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. Examples of the heteroaryl group include a pyrrole group, an indole group, a carbazole group, a furan group, and a thiophene group, and an indole group is preferable.
The aralkyl group of Ra is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group.
The alkyl group, cycloalkyl group, aryl group and aralkyl group of Ra may have a substituent. Examples of the substituent that the alkyl group, cycloalkyl group, aryl group, and aralkyl group of Ra may have include, for example, an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amide group, a ureido group, a urethane group, Examples thereof include a hydroxyl group, a carboxyl group, a halogen atom, an alkoxy group, a thioether group, an acyl group, an acyloxy group, an alkoxycarbonyl group, a cyano group, and a nitro group.

The monovalent organic group of Xa _{2 is the same as} the monovalent organic group of Ra.

The monovalent organic group of Xa ₃ and Xa _{4 is the same as} the monovalent organic group of Ra.

Examples of the divalent organic group for Xa ₁ include an alkylene group, a cycloalkylene group, an arylene group, and an alkenylene group.
The alkylene group of Xa ₁ is preferably a linear or branched alkylene group having 1 to 8 carbon atoms, and examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, and an octylene group.
The cycloalkylene group of Xa ₁ is preferably a cycloalkylene group having 5 to 12 carbon atoms, for example, a monocyclic residue such as a cyclopentylene group or a cyclohexylene group, and a polycyclic residue such as a normornan skeleton or an adamantane skeleton. Etc.
The arylene group of Xa ₁ is preferably an arylene group having 6 to 15 carbon atoms, and examples thereof include a phenylene group and a naphthylene group.
The alkenylene group of Xa ₁ is preferably an alkenylene group having 2 to 6 carbon atoms, and examples thereof include an ethenylene group, a propenylene group, and a butenylene group.
The divalent organic group of Xa ₁ may have a substituent. Examples of the substituent that the divalent organic group of Xa ₁ may have include a halogen atom such as a fluorine atom and a chlorine atom, a cyano group, and the like.

Examples of the monovalent organic group represented by R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an arylacyl group, and an arylcarbonylalkyl group.
The alkyl group, cycloalkyl group and aralkyl group for R ₂₀₁ , R ₂₀₂ and R ₂₀₃ are the same as the alkyl group, cycloalkyl group and aralkyl group for Ra.
The aryl group in R ₂₀₁ , R ₂₀₂ and R _{203, and} the aryl group in the arylacyl group and arylcarbonylalkyl group are the same as the aryl group in Ra.
Aryl acyl group of R _201, R ₂₀₂ and R _203, in the alkyl group in the arylcarbonyl group is preferably an alkyl group having 1 to 5 carbon atoms.

The monovalent organic group for R ₂₀₄ and R _{205 is the same as} the monovalent organic group for R ₂₀₁ , R ₂₀₂ and R ₂₀₃ .

The monovalent organic group for R ₂₀₆ and R _{207 is the same as} the monovalent organic group for Ra.

Examples of the anion of X ⁻ include an organic sulfonate anion (R ¹ —SO ₃ —), an organic carboxylate anion (R ¹ —CO ₂ —), and an organic imido acid anion (N ⁻ (SO ₂ —R ¹ )). ₂ ), an organic methide acid anion (C ⁻ (SO ₂ —R ¹ ) ₃ ), a halogen anion (Br ⁻ , Cl ⁻ ), BF ₄ − and PF ₆ −. As an anion of X ⁻ , an organic sulfonate anion (R ¹ —SO ₃ —), an organic carboxylate anion (R ¹ —CO ₂ —), an organic imido acid anion (N ⁻ (SO ₂ —R ¹ ) ₂ ) An organic methide acid anion (C ⁻ (SO ₂ —R ¹ ) ₃ ) is particularly preferred. Here, R ¹ represents a monovalent organic group.
The monovalent organic group for R ¹ preferably has 1 to 40 carbon atoms, and examples thereof include an alkyl group, an aryl group, and a camphor residue. A plurality of R ¹ may be the same or different and may be further substituted with a halogen atom (preferably a fluorine atom) or the like.

Examples of the compound having a structure that generates an acid upon irradiation with actinic rays or radiation include, for example, a low molecular weight compound having a molecular weight of 3000 or less having at least one structure represented by general formulas (ZI) to (ZVII) and a general formula ( Examples thereof include resins having at least one structure represented by ZI) to (ZVII).
In addition, having a structure represented by general formula (ZI)-(ZVII) may be the structure itself represented by general formula (ZI)-(ZVII), or may be represented by general formula (ZI)-( A monovalent organic group formed by losing a hydrogen atom or a monovalent organic group from the structure represented by ZVII) may be bonded.

  Examples of the low molecular weight compound having a structure that generates an acid upon irradiation with actinic rays or radiation include 1,2-naphthoquinone diazide-5-sulfonic acid ester of a polyhydric phenol compound, 1,2-naphthoquinone diazide of a polyhydric alcohol compound 5-sulfonic acid ester, polyhydric carboxylic acid hydroxyimide ester, polyhydric carboxylic acid arylcarbonylmethyl ester, and the like.

  Specific examples of the low molecular weight compound having the structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation are shown below, but the present invention is not limited thereto.

  As resin which has a structure which generate | occur | produces an acid by irradiation of actinic light or a radiation, resin which has a repeating unit which has a structure represented by general formula (ZI)-(ZVII) is mentioned, for example. Examples of the repeating unit having a structure represented by the general formulas (ZI) to (ZVII) include a repeating unit having a styrene structure, a repeating unit having a (meth) acrylic structure, a vinyl ether repeating unit, and an olefin repeating unit. It is done.

  Examples of the repeating unit having a structure that generates an acid upon irradiation with actinic rays or radiation include repeating units represented by the following general formulas (ZPI) to (ZPVI).

In the general formulas (ZPI) to (ZRVI),
Wa represents a group forming a polymer chain.
Ya ₁ represents a single bond or a divalent linking group. Preferred divalent linking groups include an arylene group, an alkylene group, a monocyclic or polycyclic alkylene group alone, or a plurality of these are a single bond or —C (O) O— bond, — (C═O). A divalent linking group formed by bonding via an NRy-bond (Ry is an alkyl or aryl group) can be exemplified.
Xa ₂ , Xa ₃ , Xa ₄ , Xa ₁ , R ₂₀₁ , R ₂₀₂ , R ₂₀₃ , R ₂₀₄ , R ₂₀₅ , R ₂₀₆ and R ₂₀₇ are Xa ₂ in general formulas (ZI) to (ZVII), Xa ₃ , Xa ₄ , Xa ₁ , R ₂₀₁ , R ₂₀₂ , R ₂₀₃ , R ₂₀₄ , R ₂₀₅ , R ₂₀₆ and R ₂₀₇ are synonymous.

  Hereinafter, although the specific example of the repeating unit which has a structure (a) which hydrophilicity increases by irradiation of actinic light or a radiation is shown, this invention is not limited to this.

The resin having the structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation has other repeating units in addition to the repeating unit having the structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation. Can have. Other preferable repeating units include alkali-soluble groups (for example, phenolic hydroxyl groups, carboxyl groups, sulfonamide groups, sulfonylimide groups, alkyl alcohols substituted with electron-withdrawing groups, etc.), hydroxyl groups, cyano groups, Decomposed by the action of an alkali group (described later) having a repeating unit having an interactive group such as a ketone group or an amide group, a repeating unit having a dry etching resistance group (an alicyclic hydrocarbon group, an aromatic group, etc.) Examples thereof include a repeating unit having a structure (b) that increases the solubility in a developer. Specific examples of the repeating unit having an alkali-soluble group include, for example, specific examples of the repeating unit having an alkali-soluble group in the resin (Ca) described later.
When the compound (A) is a resin, the content of the repeating unit having the structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation is preferably 40 to 100 mol%, more preferably 60 to 100 mol%, More preferably, it is 80-100 mol%.

A compound having a structure (b) that decomposes by the action of an alkali and increases the solubility in an alkali developer and does not have a group that decomposes by the action of an acid (also referred to as “compound (B)”)
In compound (B), “does not have a group decomposable by the action of an acid” means that there is no decomposability by the action of an acid in an image forming process in which the positive photosensitive composition of the present invention is usually used. Or it is very small and does not have the group which contributes to the image formation by acid decomposition substantially. For example, in the case of a positive chemically amplified resist, in the exposure process, the photoacid generator is decomposed in the exposed portion to generate an acid. In the post-heating step, the acid decomposes the resin having an acid-decomposable group and releases the alkali-soluble group, whereby only the exposed portion can be developed with an alkali. In the developing step, the exposed portion is selectively developed to form a pattern.
The compound (B) has no or very low decomposability due to the action of acid in this exposure and post-heating step, and has substantially no group that contributes to image formation by acid decomposition. That is, the positive photosensitive composition of the present invention has a completely different image forming mechanism from a generally known chemically amplified resist composition.

  In the compound (B), the structure (b) which decomposes by the action of an alkali and increases the solubility in an alkali developer is preferably a lactone group or an acid anhydride group, more preferably a lactone group.

  As the lactone group, any group having a lactone structure can be used, but a group having a 5- to 7-membered ring lactone structure is preferable, and a bicyclo structure or tricyclo group is added to the 5- to 7-membered ring lactone structure. Those in which other ring structures are condensed to form a structure, tetracyclo structure or spiro structure are preferred. A group having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16) is more preferable. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and a specific lactone structure is used. When used in a resist composition, line edge roughness and development defects are improved. Further, the higher the lactone alkali hydrolyzability, the better the sensitivity of the composition, which is preferable.

In the general formulas (LC1-1) to (LC1-16), the lactone structure portion may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of (Rb ₂ ) may be the same or different, and a plurality of (Rb ₂ ) may be bonded to form a ring.

  The compound (B) is decomposed by the action of the low molecular weight compound having a molecular weight of 3000 or less having the structure (b) that decomposes by the action of alkali and increases the solubility in the alkali developer and the action of alkali, and in the alkali developer. And a resin having a repeating unit having a structure (b) in which the solubility of the resin increases.

  As a low molecular weight compound having a molecular weight of 3000 or less having a structure (b) that decomposes by the action of an alkali and increases the solubility in an alkali developer, a compound having two or more lactone groups and / or acid anhydride groups is preferable. . By having a plurality, dissolution contrast is improved. As such a compound, a compound in which a lactone group and / or an acid anhydride group is bonded to an aromatic group or an alicyclic hydrocarbon group skeleton by an ester bond or an ether bond is preferable.

  Hereinafter, specific examples of low molecular weight compounds having a molecular weight of 3000 or less having a structure (b) that decomposes by the action of an alkali and increases the solubility in an alkali developer will be described, but the present invention is not limited thereto. Absent.

  As the repeating unit having a structure (b) that decomposes under the action of an alkali and increases the solubility in an alkali developer, a repeating unit having a styrene structure, a repeating unit having a (meth) acrylic structure, a vinyl ether-based repeating unit, A repeating unit in which a lactone group and / or an acid anhydride group is bonded to an olefin-based repeating unit by an ester bond or an ether bond is preferable.

  Hereinafter, although the specific example of the repeating unit which has a structure (b) which decomposes | disassembles by the effect | action of an alkali and increases the solubility in an alkali developing solution is given, this invention is not limited to this.

  In the above specific examples, Rxa represents a hydrogen atom, an optionally substituted alkyl group or a cyano group.

A resin having a repeating unit having a structure (b) that decomposes by the action of an alkali and increases in solubility in an alkali developer has a structure (b that decomposes by the action of an alkali and increases the solubility in an alkali developer. In addition to the repeating units having), other repeating units can be included. Other preferable repeating units include alkali-soluble groups (for example, phenolic hydroxyl groups, carboxyl groups, sulfonamide groups, sulfonylimide groups, alkyl alcohols substituted with electron-withdrawing groups, etc.), hydroxyl groups, cyano groups, Examples thereof include a repeating unit having an interactive group such as a ketone group or an amide group, and a repeating unit having a group having dry etching resistance (such as an alicyclic hydrocarbon group or aromatic group). Specific examples of the repeating unit having an alkali-soluble group include, for example, specific examples of the repeating unit having an alkali-soluble group in the resin (Ca) described later.
When the compound (B) is a resin, the content of the repeating unit having the structure (b) that decomposes by the action of an alkali and increases the solubility in an alkali developer is preferably 40 to 100 mol%, more preferably It is 50-100 mol%, More preferably, it is 70-100 mol%.

  When the positive photosensitive composition of the present invention is exposed to light of 150 to 220 nm to form a pattern, the compound (B) preferably does not have an aromatic structure. By not having an aromatic structure, the transmittance of the photosensitive film is improved and the sensitivity is improved.

It has a structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation, and a structure (b) which is decomposed by the action of an alkali and increases the solubility in an alkali developer, and is decomposed by the action of an acid. Compound having no group (also referred to as “compound (AB)”)
In the compound (AB), the structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation is the structure (a) in which the hydrophilicity is increased by irradiation with actinic rays or radiation in the compound (A) component ( The same thing as a) is mentioned.
The structure (b) that decomposes by the action of an alkali and increases the solubility in an alkali developer is a structure in the compound (B) that decomposes by the action of an alkali and increases the solubility in an alkali developer. The same thing as (b) is mentioned.
The phrase “having no group decomposable by the action of an acid” has the same meaning as “having no group decomposable by the action of an acid” in the compound (B).

  As the compound (AB), for example, a molecular weight having a structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation and a structure (b) which is decomposed by the action of an alkali and increases the solubility in an alkali developer. A low molecular weight compound having a molecular weight of 3000 or less, and a structure (b) that is decomposed by the action of an alkali and a repeating unit having a structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation, and has increased solubility in an alkali developer (b And a resin having a repeating unit.

  Hereinafter, a low molecular weight compound having a molecular weight of 3000 or less having a structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation and a structure (b) which is decomposed by the action of alkali and has increased solubility in an alkali developer. Although a specific example is given, this invention is not limited to this.

When the compound (AB) is a resin, the compound (AB) is decomposed by the action of the repeating unit having the structure (a) whose hydrophilicity increases by irradiation with actinic rays or radiation and the alkali, and has a solubility in an alkali developer. In addition to the repeating unit having the structure (b) in which is increased, other repeating units can be included. Other preferable repeating units include alkali-soluble groups (for example, phenolic hydroxyl groups, carboxyl groups, sulfonamide groups, sulfonylimide groups, alkyl alcohols substituted with electron-withdrawing groups, etc.), hydroxyl groups, cyano groups, Examples thereof include a repeating unit having an interactive group such as a ketone group or an amide group, and a repeating unit having a group having dry etching resistance (such as an alicyclic hydrocarbon group or aromatic group). Specific examples of the repeating unit having an alkali-soluble group include, for example, specific examples of the repeating unit having an alkali-soluble group in the resin (Ca) described later.
When the compound (AB) is a resin, the content of the repeating unit having the structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation is preferably 1 to 70 mol%, more preferably 3 to 50 mol%, More preferably, it is 5-30 mol%.
When the compound (AB) is a resin, the content of the repeating unit having the structure (b) that decomposes by the action of an alkali and increases the solubility in an alkali developer is preferably 30 to 99 mol%, more preferably It is 40-97 mol%, More preferably, it is 50-95 mol%.
When the positive photosensitive composition of the present invention is exposed to light of 150 to 220 nm to form a pattern, the content of the aromatic structure in the compound (AB) is preferably 20 mol% or less. When the compound (AB) is a resin, the content of the repeating unit having an aromatic structure is preferably 20 mol% or less. By reducing the content of the aromatic group, the transmittance of the photosensitive film is improved and the sensitivity is improved.

As a preferable aspect of the positive photosensitive composition of the present invention,
(I) an embodiment containing compound (A) and compound (B), wherein compound (A) is a resin, and compound (B) is a low molecular compound,
(Ii) an embodiment containing compound (A) and compound (B), wherein compound (A) is a low molecular compound, and compound (B) is a resin;
(Iii) A mode in which the compound (A) and the compound (B) are contained, and both the compound (A) and the compound (B) are resins, or the compound (AB) is contained, and the compound (AB) is a resin. ,
(Iv) an embodiment containing the compound (A) and the compound (B), wherein the compound (A) and the compound (B) are low molecular weight compounds or resins, and further containing another resin (C),
(V) a compound (AB), wherein the compound (AB) is a low molecular compound or a resin, and further contains another resin (C); and (vi) a compound (AB), The aspect which contains a compound (A) and / or a compound (B), and at least one of a compound (AB), a compound (A), and a compound (B) is resin can be mentioned.

Other Resin The positive photosensitive composition of the present invention further contains another resin (also referred to as “resin (C)”) in addition to the compound (A), the compound (B), and the compound (AB). be able to.
The resin (C) is preferably a resin having a repeating unit having an alkali-soluble group (also referred to as “resin (Ca)”).
The repeating unit having an alkali-soluble group is preferably a repeating unit having a styrene structure, a repeating unit having a (meth) acrylic structure, a vinyl ether-based repeating unit, or an olefin-based repeating unit, and having an alkali-soluble group. The alkali-soluble group is preferably a phenolic hydroxyl group, a carboxyl group, a sulfonamide group, a sulfonylimide group, an alkyl alcohol substituted with an electron-withdrawing group, or a methylene group sandwiched between electron-withdrawing groups, more preferably a phenolic group. A hydroxyl group and a carboxyl group;

  Hereinafter, although the specific example of the repeating unit which has an alkali-soluble group is given, this invention is not limited to this.

The resin or the other resin (C) in the compound (A), the compound (B), and the compound (AB) can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used in the composition of the present invention. Thereby, the generation of particles during storage can be suppressed.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.
The weight average molecular weight of the resin is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, and most preferably 5,000 to 15,000 as a polystyrene-converted value by the GPC method. is there. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, developability is deteriorated, and viscosity is increased, resulting in deterioration of film forming property. Can be prevented.
The molecular weight distribution is usually 1 to 5, preferably 1 to 3, more preferably 1 to 2. The smaller the molecular weight distribution, the better the resolution and the resist shape, and the smoother the side wall of the resist pattern, the better the roughness.

In the positive photosensitive composition of the present invention, the compounding amount of the compound (A) is preferably 1 to 50% by mass, more preferably 3 to 40% by mass, and particularly preferably 5 to 30% by mass in the total solid content. %.
In the positive photosensitive composition of the present invention, the compounding amount of the compound (B) is 30 to 9 in the total solid content.
9 mass% is preferable, More preferably, it is 60-97 mass%, Most preferably, it is 70-95 mass%.
In the positive photosensitive composition of the present invention, the compounding amount of the compound (AB) is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, and particularly preferably 80 to 100% by mass in the total solid content. %.

  When used in photoresist applications, the positive photosensitive composition of the present invention preferably contains an aromatic structure or an alicyclic hydrocarbon structure in order to improve dry etching resistance.

Fluorine and / or silicon surfactant The positive photosensitive composition of the present invention further comprises a fluorine and / or silicon surfactant (fluorine surfactant and silicon surfactant, fluorine atom and silicon atom). It is preferable to contain any one of these, or two or more of them.

  When the positive photosensitive composition of the present invention contains fluorine and / or a silicon-based surfactant, adhesion and development with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. A resist pattern with few defects can be provided.

  Examples of these fluorine and / or silicon surfactants include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.

  Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), etc. Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

  In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.

As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. It may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxy) (Ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate) copolymer, acrylate (or methacrylate) and (poly (oxyalkylene)) acrylate having C ₈ F ₁₇ groups (or Copolymer of acrylate (or methacrylate), (poly (oxyethylene)) acrylate (or methacrylate), and (poly (oxypropylene)) acrylate (or methacrylate) having a C ₈ F ₁₇ group Coalesce, etc. Can.

  The amount of fluorine and / or silicon-based surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the positive photosensitive composition (excluding the solvent). %.

Organic Solvent The positive photosensitive composition of the present invention is used by dissolving the above components in a predetermined organic solvent.
Examples of the organic solvent that can be used include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl. Ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N -Dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran, etc. Preferred solvents include propylene glycol monomethyl ether acetate, cyclohexanone, propylene glycol monomethyl ether, and ethyl lactate.

In the present invention, the organic solvent may be used alone or in combination, but it is preferable to use a mixed solvent containing two or more solvents having different functional groups. As a result, the solubility of the material is increased, and not only the generation of particles over time can be suppressed, but also a good pattern profile can be obtained. Preferable functional groups contained in the solvent include ester groups, lactone groups, hydroxyl groups, ketone groups, and carbonate groups. As the mixed solvent having different functional groups, the following mixed solvents (S1) to (S5) are preferable.
(S1) a mixed solvent obtained by mixing a solvent containing a hydroxyl group and a solvent not containing a hydroxyl group,
(S2) a mixed solvent obtained by mixing a solvent having an ester structure and a solvent having a ketone structure;
(S3) a mixed solvent obtained by mixing a solvent having an ester structure and a solvent having a lactone structure;
(S4) a mixed solvent obtained by mixing a solvent having an ester structure, a solvent having a lactone structure, and a solvent containing a hydroxyl group;
(S5) A mixed solvent obtained by mixing a solvent having an ester structure, a solvent having a carbonate structure, and a solvent containing a hydroxyl group.
As a result, the generation of particles during storage of the resist solution can be reduced, and the generation of defects during application can be suppressed.

  Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. And propylene glycol monomethyl ether and ethyl lactate are more preferred.

  Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are more preferable, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone and cyclohexanone are particularly preferred.

Examples of the solvent having a ketone structure include cyclohexanone and 2-heptanone, and cyclohexanone is more preferable.
Examples of the solvent having an ester structure include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, and butyl acetate, and propylene glycol monomethyl ether acetate is more preferable.
Examples of the solvent having a lactone structure include γ-butyrolactone.
Examples of the solvent having a carbonate structure include propylene carbonate and ethylene carbonate, and propylene carbonate is more preferable.
The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.
The mixing ratio (mass) of the solvent having an ester structure and the solvent having a ketone structure is 1/99 to 99/1, preferably 10/90 to 90/10, and more preferably 40/60 to 80/20. . A mixed solvent containing 50% by mass or more of a solvent having an ester structure is particularly preferable from the viewpoint of coating uniformity.
The mixing ratio (mass) of the solvent having an ester structure and the solvent having a lactone structure is 70/30 to 99/1, preferably 80/20 to 99/1, and more preferably 90/10 to 99/1. . A mixed solvent containing 70% by mass or more of a solvent having an ester structure is particularly preferable from the viewpoint of stability over time.
When mixing a solvent having an ester structure, a solvent having a lactone structure, and a solvent containing a hydroxyl group, the solvent having an ester structure is 30 to 80% by weight, the solvent having a lactone structure is 1 to 20% by weight, and the hydroxyl group is contained. It is preferable to contain 10 to 60% by weight of the solvent.
When mixing a solvent having an ester structure, a solvent having a carbonate structure and a solvent containing a hydroxyl group, the solvent having an ester structure is 30 to 80% by weight, the solvent having a carbonate structure is 1 to 20% by weight, and the hydroxyl group is contained. It is preferable to contain 10 to 60% by weight of the solvent.

<Other additives>
The positive photosensitive composition of the present invention further contains dyes, pigments, plasticizers, surfactants other than the above, photosensitizers, and compounds that promote solubility in a developer as necessary. be able to.

  The dissolution accelerating compound for the developer that can be used in the present invention is a low molecular weight compound having a molecular weight of 1,000 or less and having two or more phenolic OH groups or one or more carboxy groups. When it has a carboxy group, an alicyclic or aliphatic compound is preferable.

  The preferable addition amount of these dissolution promoting compounds is 2 to 50% by mass, and more preferably 5 to 30% by mass with respect to the acid-decomposable resin. The amount is preferably 50% by mass or less from the viewpoint of suppressing development residue and preventing pattern deformation during development.

  Such phenolic compounds having a molecular weight of 1000 or less can be obtained by referring to methods described in, for example, JP-A-4-1222938, JP-A-2-28531, U.S. Pat. No. 4,916,210, European Patent 219294, and the like. Can be easily synthesized.

  Specific examples of alicyclic or aliphatic compounds having a carboxyl group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

  In the present invention, a surfactant other than the fluorine-based and / or silicon-based surfactant may be added. Specifically, nonionic interfaces such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan aliphatic esters, polyoxyethylene sorbitan aliphatic esters, etc. Mention may be made of activators.

  These surfactants may be added alone or in some combination.

(Pattern formation method)
In the positive photosensitive composition of the present invention, the above components are dissolved in a predetermined organic solvent, preferably the mixed solvent, filtered as necessary, and then applied onto a predetermined support as follows. Use. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon of 0.1 microns or less, more preferably 0.05 microns or less, and still more preferably 0.03 microns or less.

For example, in the case of a semiconductor resist application, a positive photosensitive composition is applied onto a substrate (eg, silicon / silicon dioxide coating) used for manufacturing a precision integrated circuit element by an appropriate application method such as a spinner or a coater. , Dried to form a photosensitive film.
Examples of other supports include an aluminum substrate and a glass substrate.
The photosensitive film is irradiated with actinic rays or radiation through a predetermined mask, baked (heated) as necessary, and developed and rinsed. Thereby, a good pattern can be obtained.
Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a refractive index higher than air between the photosensitive film and the lens of the exposure apparatus during irradiation with actinic rays or radiation. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a higher refractive index than air, but pure water is preferred. Further, an overcoat layer may be further provided on the photosensitive film so that the immersion medium and the photosensitive film do not come into direct contact with each other during the immersion exposure. Thereby, the elution of the composition from the photosensitive film to the immersion medium is suppressed, and development defects are reduced.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., but preferably far ultraviolet light having a wavelength of 400 nm or less, more preferably 250 nm or less. Specifically, 365 nm, 254 nm, KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), F ₂ excimer laser light (157 nm), X-ray, EUV (13 nm), electron beam, etc., KrF Excimer laser, ArF excimer laser, F ₂ excimer laser, EUV, and electron beam are preferred.

In the development step, an alkaline developer is used as follows. Examples of the alkaline developer of the composition include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine Secondary amines such as di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide and the like. Alkaline aqueous solutions of cyclic amines such as quaternary ammonium salts, pyrrole and pihelidine can be used.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline developer.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass.
The pH of the alkali developer is usually from 10.0 to 14.0.
The photosensitive film is brought into contact with these developers to remove the exposed portion.

Synthesis Example 1 (Synthesis of resin (R1))
Under a nitrogen stream, 10.6 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. To this, 25.6 g of the following monomer A, 0.86 g of methacrylic acid, and 8 mol% of the polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries) dissolved in 95.2 g of cyclohexanone with respect to the monomer were taken for 6 hours. And dripped. After completion of dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then poured into 900 ml of hexane / 100 ml of ethyl acetate, and the precipitated powder was collected by filtration and dried to obtain 22 g of Resin (R1). The weight average molecular weight of the obtained resin (R1) was 8300 in terms of polystyrene, and the dispersity (Mw / Mn) was 1.92.

Synthesis Example 2 (Synthesis of Compound (X1))
10 g of 1,3-adamantane dicarboxylic acid and 18.4 g of α-bromo-γ-butyrolactone were dissolved in 100 ml of methyl isobutyl ketone. To this solution, 14.6 g of triethylamine was added dropwise over 30 minutes and allowed to react at room temperature for 15 hours. The reaction solution was poured into a solution of 20 ml of hydrochloric acid in 500 ml of distilled water and extracted with ethyl acetate. The organic phase was washed with water, dried and concentrated to give a crude product. When this is purified by column chromatography, the compound (
10.2 g of X1) was obtained.

Examples 1 to 13 and Comparative Example 1
<Preparation of positive photosensitive composition>
The components shown in Table 1 below and 0.01 g of Troysol S-366 (fluorine surfactant manufactured by Troy Chemical Co., Ltd.) are dissolved in 90 g of cyclohexanone, and this is filtered through a 0.03 m polyethylene filter, and positive photosensitive. A sex composition was prepared.

  Abbreviations in Table 1 are as follows.

<Low pressure mercury lamp evaluation>
The positive photosensitive compositions of Examples 1 to 13 were applied on a silicon substrate subjected to hexamethyldisilazane treatment with a spin coater and dried at 110 ° C. for 90 seconds to form a 250 nm photosensitive film. . A low-pressure mercury lamp was used to irradiate a 1 cm ² pattern with an exposure dose of 50 mJ / cm ² . This was developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds and rinsed with pure water for 30 seconds. Only the exposed area was selectively dissolved, and the unexposed area was observed to be reduced in film thickness. I couldn't.
Further, after the exposure, heating was performed at 100 ° C. for 60 seconds, and development and rinsing were performed in the same manner, and the same result as that obtained when no heating was performed was obtained.
<Evaluation of KrF excimer laser resist>
About the positive photosensitive composition of Examples 1-13, it apply | coated on the silicon substrate which performed the hexamethyldisilazane process with the spin coater, and it dried at 110 degreeC for 90 second, and formed the 250-nm photosensitive film | membrane. . This photosensitive film is exposed with a KrF excimer laser stepper (NA = 0.63 manufactured by Canon Inc.) through a mask, left in a clean room controlled to have an ammonia concentration of 5 ppb or less for 30 minutes, and then hot at 110 ° C. for 60 seconds. Heated on plate. Further, the resist film was developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and then dried to obtain a line pattern. When observed using a length measuring scanning electron microscope (SEM), 200 nm line and space 1/1 was resolved (sample 1).
After the exposure, an experiment similar to Sample 1 was performed except that the sample was left in a laboratory where the ammonia concentration was not controlled for 30 minutes. As a result, a 200 nm line and space 1/1 was similarly resolved (Sample 2). .
Immediately after the exposure, the same development treatment as in Sample 1 was performed without heating, and a 200 nm line and space 1/1 was similarly resolved (Sample 3).
When the same evaluation was performed on the positive photosensitive composition (chemically amplified positive photosensitive composition) of Comparative Example 1, the sample 1 had a resolution of 200 nm line and space 1/1. In Sample 2, the film surface remained undeveloped even in the exposed part (T-Top shape), and the 200 nm line and space 1/1 was not resolved. In sample 3, the entire surface remained, and no pattern was formed.
<ArF excimer laser resist evaluation>
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied onto a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. The positive photosensitive compositions of Examples 1, 2, 3, 4, 6, and 8 were applied with a spin coater and dried at 120 ° C. for 90 seconds to form a 120 nm resist film. The resist film was exposed with an ArF excimer laser stepper (NA = 0.75 manufactured by ASML) through a mask, and immediately after the exposure, it was heated on a hot plate at 120 ° C. for 90 seconds. Further, the resist film was developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and then dried to obtain a line pattern. When observed using a length-measuring scanning electron microscope (SEM), 150 nm line and space 1/1 was resolved.
From the above results, it is clear that the positive photosensitive composition of the present invention has a very low influence on the environment and high resolution.

Claims (7)

(A) a compound having a structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation, and (B) a structure (b) which is decomposed by the action of an alkali and increases the solubility in an alkali developer. And a positive photosensitive composition comprising a compound having no group capable of decomposing by the action of an acid. (AB) a structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation, a structure (b) which is decomposed by the action of alkali and has a structure (b) whose solubility in an alkali developer is increased, and the action of acid A positive photosensitive composition comprising a compound that does not have a group capable of decomposing by.   The positive photosensitive composition according to claim 1 or 2, wherein the structure (b) which decomposes under the action of an alkali and increases the solubility in an alkali developer is a lactone group or an acid anhydride group. object.   The positive structure according to any one of claims 1 to 3, wherein the structure (a) whose hydrophilicity is increased by irradiation with actinic rays or radiation is a structure which generates an acid upon irradiation with actinic rays or radiation. Photosensitive composition.   5. The compound according to claim 1, wherein at least one compound selected from the compound (A), the compound (B), and the compound (AB) further has an alkali-soluble group. The positive photosensitive composition described in 1.   The positive photosensitive composition according to any one of claims 1 to 5, further comprising (Ca) a resin having an alkali-soluble group.   A pattern forming method comprising the steps of: forming a photosensitive film from the positive photosensitive composition according to claim 1; and exposing and developing the photosensitive film.